Preamp for my CODA 5.5 amp

FWIW, this most likely won't be of any help but I am using the Legacy Audio Wavelet II into my Coda S5.5 which is driving the mid/treble of my Legacy Focus XD's. The Waveet is also an external crossover and has Room Correction DSP specifically programmed for the speakers I have. The Coda amps pair exceptionally well with the Legacy speakers. 

 My Backert Labs Rumba tube hybrid preamp has great synergy with the S5.5, adding in some beautiful tube harmonics combined with hi resolution. 

Like @yyzsantabarbara I was using a Holo Audio Serene KTE on my Coda #8 with good results. Very transparent sounding. I now have a Balanced Audio Technology (BAT) VK-80 Tube preamp that I am extremely happy with. Sold my Serene preamp.

You’d get much better and more targeted recommendations if you share what specific improvements you’re looking for and what sound characteristics in general are most important to you.  Do you find the Coda to be sufficient to drive your Aerials?

@willywonka this thread got me to thinking of a tube preamp for my #16. I was trying to remember what preamp you switched to from the Serene. Glad you posted the comment above. I owned a BAT VK-42SE preamp long ago, but it was solid state.

The Serene is a nice preamp however, I was very disappointed when I took it to my friend's house (Danny from RAAL) and I put the Serene into his system. It was good but the preamp he had built just outclassed the Serene.

The preamp I really love is the Benchmark LA4 or HPA4. I have this in my office system.

BTW - I repurchased the RAAL SR1a earphone and VM-1a. I think you owned the SR1a at one time. I realized after some demos that the SR1a was really the best.